Patent GB-572901-A (GB)
Title: Improvements in control systems for travelling machines
IPC: B66C15/04
Filed: 1943-07-08
Abstract: 572,901. Control system for travelling machines. IGRANIC ELECTRIC CO., Ltd. July 8, 1943, No. 11107. Convention date, July 10, 1942. [Class 105] Power-propelled travelling machines such as overhead cranes are prevented from approaching too closely by the propulsion power being cut off by an electrical control on too close an approach, this electrical control, however, not being effective on the machine which has its controller for the propulsion power set in position for away travel. In the arrangement shown an approaching machine has its propulsion power cut off by the deenergization of an under-voltage relay caused by an electrical control arising when a trolley of such machine engages a length of sectionalized conductor rail already engaged by the trolley of the other machine. The motor control panels of two travelling machines are shown as having drum switches 9, 10 which in the unoperated position effect the energization of the under-voltage relays UV1, UV2 but when a drum switch 9 or 10 is moved to an operated position to initiate overtaking travel by one machine the under-voltage relay of such machine will remain energized by a stick circuit including a front contact of a control relay CR only if such control relay CR is not de-energized by the trolleys 24 of the two machines being on the same length of the sectionalized conductor. The relay UV1 is picked up by current from electric supply conductor T1 through a trolley 20, wire 32, segments 12a, 13a of drum switch 9, wire 33, winding 8, a trolley 21, and electric supply conductor T2. When the drum switch 9 is moved to initiate travel to the right hand the relay UV1 is maintained energized by a stick circuit from wire 32 over front contact 16 of control relay CR and stick contact 6. The control relay CR is energized from wire 32, through winding 15 a resistance R, and the trolley 21 but is, however, short-circuited when the trolley 24 of this machine engages the same length of sectionalized conducter 25a as the trolley 24 of the other machine since trolley 20 of this other machine applies power from supply conductor T1, wires 30, 41, the length 25a and wire 40 joined to the resistance R which limits the current. With control relay CR thus shunted out the under-voltage relay UV1 becomes de-energized so to stop the motor. If the drum switch 9 had been set to the position to initiate travel to the left hand the relay. UV1 would be maintained energized by a stick circuit from wire 32, segments 12a, 14a, and a stick contact 7 and so would not be affected by the dropping of the control relay CR when the other machine reached the same length 25a of the sectionalized conductor. In this case, however, the dropping of the control relay CR opens front contact 17 in the stick circuit for the under-voltage UV2 of such other machine this circuit including trolleys 22 of the two machines, a continuous conductor 23, and stick contact 6 of the relay UV2; thus the motor of this other machine would be stopped since the drum switch 10 being set for left hand travel of the machine the other stick circuit for relay UV2 over stick contact 7, segments 14b, 12a would be open.